Dead Tilapia

[Moses Greengrass]

I really should be smarter and keep a better record of everything. On July 7th I added chelated Iron to my system because the plants were looking anemic which I think is due to high PH. July 8th the first floater popped up and since then 270 tilapia died. The dying stopped but the water is to murky to see any fish in there but according to my counting I have about 90 fish left. I have been testing the nitrites and ammonia and have been at zero ppm each time. I don't think a very small amount of chelated Iron could do that to my fish especially since I have almost 4000 gallons circulating through my system. I feel like I should have been more pro active in rescuing fish but I operate a small landscaping company and we have been busy. Regardless, this should have been a learning experience but it wasn't. I just counted dead fish for two weeks which doesn't seem very productive. Moving forward I would like to avoid any problems like this, but I'm not sure what the problem really was or is. I can start answering questions for anyone who is interested in helping me diagnose. I'm not very knowledgeable in the world of fish culture or aquaponics. Any help would be great!

[TCLynx]

Yes Chris, at least in a way.  The warmer the water, the less dissolved oxygen it can hold so as the temperature rises you need more aeration to replace any used up dissolved oxygen as quickly as possible since there is less available in the water in the first place.

 

During the bright sunny hours of the day, algae will provide dissolved oxygen to the water but as soon as it gets dark, plants start consuming oxygen.  If the water is warm (read not much dissolved oxygen in it) and there isn't enough aeration going on, at night algae can quickly use up all the dissolved oxygen and leave the fish gasping at the surface before morning and in some cases dead by morning.

[Raychel A Watkins]

I just walked out to my systems this am and found 4 dead Tilipia floating on the top of one of my 180 gal rubbermaid tanks.  This tank has been up for a year with no problems.  As someone pointed out they looked like the had been dead awhile.  The water was a little murky and has always been clear before.  I did all the tests no Ammonia , pH good nitrates good.  I tried to figure what had happened.  The only thing I could think of was that my son in law had sawed some boards for a new system around that tank and I had noticed the saw dust on the grow bed.  I immediately took the water down twice and filled with fresh water.  I was gone all day but this evening When I went out the water was clear and all fish looked fine.  I believe the saw dust was toxic.  It was old wood probably treated.  I have added cheated iron many times and never a problem.  One day I moved 60 tilapia out of a tank just because the ammonia was too high.  They were having no problem with the ammonia.  I put them in  a new tank I had never used before.  the next morning 48 were dead.  The pH was 8.5.  The tank was not cleaned properly.  So much for me giving the fish some relief from the ammonia.  I have since cleaned the tank properly and have happy fish living in it,  If you find some dead ones you have to do something about the water now not later.  I did save 12 fish by moving them to another tank I new was safe.  It hurts when these things happen.  It sure doesn't sound like you were overloaded in the system.  Is the system new?  Is there anything in the systems structure that could be toxic.  I and another person killed a bunch of baby catfish because we used new kids swimming pools.  Think about what it does to children.

[Harold Sukhbir]

Hi Moses,

You've said that you found some uneaten food somewhere in your system and yet you are having zero ammonia and nitrites? Decaying food shoots ammonia through the roof.

[Larry Reinhardt]

My water here in central FLorida comes out of the ground at 6.0 PH and has no buffering ability at all. So when I make a serious water change I get PH bounce and the water quickly goes through the roof - off the chart in just a few hours. This is serious stress to the fish and results in belly up the next day. I have to keep Crushed Coral in the filter systems to prevent this from happening. I lost a lot of fish until one day I checked the PH every two hours after adding just 50% new water the change in PH was a real eye opener.

[TCLynx]

Wow Larry!!!!  I'm jealous as my well water is full of limestone (pH ranges between 8-8.4 depending on time of year, well is at least 126 feet deep as that is where the pump is sitting) so I've been having issues with my pH staying too high from just simply topping up let alone doing water changes.  Kinda amazes me that you have acidic well water and you don't live all that far from me!  Just goes to show that source water can have a huge impact on how an aquaponic system will operate and what methods will need to be used to balance things.

 

At least with Aquaponics we normally don't do water changes, mostly only topping up.  For people with extreme source water I usually suggest a tank for prepping the water before putting it in the system.  Some people need to bring the pH down on their source water before adding it to the system and adding acid directly to an AP system can cause those dangerous pH bounces.  Seems some people may need to buffer their rain water or well water a little bit before adding to the system.  In aquaponics calcium carbonate is often alternated with some potassium buffer to help keep the potassium and calcium levels in balance and provide the needed potassium to the plants.

[Larry Reinhardt]

This is the second place I've lived that had acid water and the water needs no treatment its good to drink as is. My next door neighbor who is only a 125' away has water full of iron and other junk, they had to have a $3,000 water treatment system put in and they still won't drink the water. They drilled down 152' to get good water and the pump is set at 85' so that tells they punched into an pressurized aquifer of some sort.

The crushed coral prevents the bounce and keeps my water right at 7, so that's a good thing I believe.

TCLynx said:

Wow Larry!!!!  I'm jealous as my well water is full of limestone (pH ranges between 8-8.4 depending on time of year, well is at least 126 feet deep as that is where the pump is sitting) so I've been having issues with my pH staying too high from just simply topping up let alone doing water changes.  Kinda amazes me that you have acidic well water and you don't live all that far from me!  Just goes to show that source water can have a huge impact on how an aquaponic system will operate and what methods will need to be used to balance things.

 

At least with Aquaponics we normally don't do water changes, mostly only topping up.  For people with extreme source water I usually suggest a tank for prepping the water before putting it in the system.  Some people need to bring the pH down on their source water before adding it to the system and adding acid directly to an AP system can cause those dangerous pH bounces.  Seems some people may need to buffer their rain water or well water a little bit before adding to the system.  In aquaponics calcium carbonate is often alternated with some potassium buffer to help keep the potassium and calcium levels in balance and provide the needed potassium to the plants.

[TCLynx]

I'm happy to drink our water, the washing machine and hot water heater probably wish I would filter the water more though.